It is not all that unusual these days to
find homes with more than one computer. As well, many
people have found numerous benefits networking their home
computers together. You can share printers and files,
play games over the network and more. Modern operating
systems make networking relatively simple and
straightforward. (If you disagree, let me know and I will
consider some articles on Windows networking.)
One thing Windows networking has not made easy is
sharing a modem. This generally translates into the
machine with an Internet connection (in other words your
computer!) being in highest demand. You can turn to Proxy
Servers or Network Address Translation (NAT) to get your
Both Proxy Servers and NAT start with the same basic
idea. They are software components that run on a machine
with an Internet connection, which may be a dial-up
modem, ISDN line, cable modem, or ADSL modem. Client
computers on your network pass requests for Internet
services to the Proxy Server or NAT gateway; in turn,
these requests are sent to the Internet. Packets coming
in from the Internet are accepted by the Proxy Server or
NAT gateway and passed on to the appropriate client
computer. Only the computer acting as proxy or NAT
gateway needs a valid Internet-routable IP address. Other
computers on your LAN are assigned IP addresses set aside
for private networks.
Proxy Server headaches
Proxy Servers are somewhat complex beasts. I used to
use WinGate 2.1d from Deerfield Communications. The
server portion was fairly straightforward to configure.
Clients were a bit more difficult. You must configure
your software to work through a Proxy Server. In some
cases, this is simple: for example, Internet Explorer has
a menu option that directs it to use a Proxy Server.
Other programs were neither easy nor possible to use
through a Proxy Server. I could never configure Microsoft
Outlook to work through WinGate 2.1 to access an Exchange
Server. Another problem I had was being able to access
multiple news servers. The first one was relatively easy
to configure. Subsequent news servers, while possible,
were a pain to configure. I never did manage to get
Telnet to work through WinGate.
I read on an Internet mail list that NAT was easier
and more capable: I went looking. WinGate 3.0 had just
been released, but I had a recommendation of SyGate 2.0
from SyberGen Inc. and I decided to try it. By the time
you read this, version 3.0 should be available.
You install the software on the machine with the
Internet connection; it must be running Windows 95, 98,
or NT4.0. SyberGen lists the minimum system requirements
as a 486 with 16MB RAM and 10MB disk space. If you hope
to use the machine for anything more than just SyGate, I
think a more realistic minimum is 32MB RAM-my recommended
minimum for running any 32-bit version of Windows. Other
computers on your LAN can be running just about any
operating system as long as they have a TCP/IP stack.
I was surprised at how easy it was to set up SyGate.
You must specify the connection type since permanent
connections such as ADSL or cable modem are handled
differently than dial-up connections. If you are using
ADSL or cable modem, you need two network cards in the
SyGate gateway machine. One connects to the ADSL or cable
modem and the other to your internal LAN. If you use a
dial-up connection to the Internet, you specify the DUN
connectoid to use. Optionally, you can set a time-out
value and the SyGate machine will hang up the connection
after a period of inactivity.
After that, you configure TCP/IP on each machine on
your LAN. The SyGate manual gives very clear instructions.
Since SyGate has a DHCP server included, you don't even
have to assign most TCP/IP settings-just by telling each
client computer to use DHCP and the IP address, the
SyGate machine sets the Network Mask, Gateway, and DNS.
If you prefer, you can disable the DHCP server and set
all TCP/IP settings manually. Again, the SyGate manual
provides very clear instructions.
At this point, you should be able to run virtually any
Internet application from any machine on the LAN. If a
connection to the Internet is not open, the SyGate
machine will establish one automatically. If you are
concerned about the possibility of automatic connections
being opened and left open, you can turn this feature off.
The most difficult area for me was to reconfigure my
Internet apps to cease using a proxy server. That is the
beauty of a NAT gateway. You simply configure most
applications as if you have a permanent connection to the
Internet and they work! I tested e-mail programs (accessing
both POP3 and Exchange Servers), FTP clients, Telnet
clients, PING, News readers, Network Time Protocol
clients, a WinFrame client, and more.
I originally had some problems accessing my Exchange
Server. Once I added the NetBIOS name of my Exchange
Server to my HOSTS file (which was not required when
accessing my Exchange Server from the machine running
SyGate) I was able to connect to my Exchange Server. Keep
this in mind when using a program like SyGate. Even
though most programs should work fine, you may run into
some programs that act differently under SyGate. Another
example is ICQ: it will require a few special settings
that are detailed in the SyGate manual.
SyGate includes a monitor that you can use to see the
traffic flowing to and from client computers and the
Internet. You can also enable and disable SyGate, but I
found that disabling SyGate disabled the Internet
connection on the SyGate machine. Only a re-boot could re-enable
It is really nice to be able to use all my Internet
applications from any computer on the network. The nature
of many Internet connections tends to be "bursty"-short
spurts of lots of traffic followed by extended periods of
little or no traffic. This lends itself well to sharing a
connection. Even a 28.8Kb dial-up connection may be
shared by several users. In many cases, users will not
notice that they are sharing the connection.
You can download SyGate from www.sygate.com. The
version you download will allow you to transfer 75MB of
data, which should be enough to verify if it works for
you. The 23-page User Guide is available in HTML and
Adobe Acrobat formats.
You can register your copy of SyGate to unlock it for
unlimited traffic. All licenses are for simultaneous
connections and a user on the SyGate machine is never
counted. Prices in US dollars are: 3 users - $49; 6 users
- $99; and unlimited - $199.
Membership has its rewards
OPCUG members can get a 15% discount by registering at
and entering "ZX0398" (that's ZX'zero'398) as
the OEM code.
If you want to read more on NAT, it is defined in RFC1631
and is available in the Internet file area on PUB II as
Maybe now, you can get back on your own computer
Sygate (Proprietary, $49 - 3 users)
Originally published: November, 1999